Cable and wire stripper

ABSTRACT

A tool for stripping the sheath from a cable including a plunger slidably positioned in a housing. A cable opening in the side is provided enabling a user to position the cable between a roller inside the housing and the end surface of the plunger. The end surface of the plunger has a cutter blade that penetrates the sheath of the cable positioned between the roller and the surface of the plunger so that, when the cable is pulled through the cable opening, an axially directed slit is formed in the sheath of the cable enabling the user to peel off the sheath.

FIELD OF THE INVENTION

[0001] This invention relates to strippers for removing insulating shields from wire and cable and particularly to a wire stripper for removing the insulating shield from ROMEX cable.

BACKGROUND AND INFORMATION DISCLOSURE

[0002] The typical electrical cable is a bundle of two or more wires, each of which has an elastomeric coat. The bundle of coated wires is encased in a tough sheath. A frequent chore involved in installing such electrical cables is the requirement to strip the sheath, usually about four to six inches from the end of the cable. For many years, the electrician used a knife to peel the sheath from the cable.

[0003] Using a knife to peel the sheath without cutting the coating on the wire required considerable care and effort and led to the development of a number of stripping tools.

[0004] U.S. Pat. No. 5,673,486 to Brown discloses a stripper having a rotatable cutting head with a cutting blade carrier block that pivots between an operative and inoperative position. The cutting head forms annular slits which form annular slugs that are removed after the wire is withdrawn from the device.

[0005] U.S. Pat. No. 5,7132,249 to Liversidge discloses a main body having a pair of clamping jaws and a pair of stripping jaws and an actuator to effect linear sliding motion of the stripper jaws.

[0006] U.S. Pat. No. 6,018,873 to McClellan discloses a stripper including a plurality of replaceable blades and an indented guide surface having a slot having a width selectable according to the size of the wire.

[0007] U.S. Pat. No. 6,079,105 to Hollingsworth discloses a tool having a blade carrying portion attached to a first portion of a handle and guide portion. The guide portion includes a channel defining a longitudinal axis and a blade. The blade is pivotable between a first cutting direction and a second cutting direction.

[0008] U.S. Pat. No. 6,330,839 to Amrein discloses means for compressing the exposed shielding to deform the shield to assume a donut shape. A cutting unit is movable transversely to a longitudinal orientation and shears off circular sections of the shielding portion.

SUMMARY OF THE INVENTION

[0009] It is an object of this invention to provide a tool that provides axially directed slits in cable sheath preparatory to stripping the sheath from the cable.

[0010] It is contemplated that the length of the slit be easily measured and controlled.

[0011] It is another object that the sheath be cut around its periphery in order to facilitate complete removal of the sheath.

[0012] It is another object that the use of the tool inherently requires less effort than characterizes stripping tools of the current art.

[0013] In one embodiment, this invention is directed toward a housing that supports a cable clamp. One jaw of the clamp is a roller. The opposing jaw has a blade extending toward the roller from a clamping surface of the opposing jaw. The cable is inserted between the clamping jaws so that the blade penetrates the sheath. The cable is pulled through the housing causing the blade to cut the sheath in the axial direction.

[0014] In yet another embodiment, the opposing jaw comprises a blade sandwiched between two rollers so that the cable passing through the device is supported entirely by rollers.

[0015] In another embodiment, a second cutter is slideably positionable on the outside surface of the housing that permits the user to cut the sheath annually by sliding the second blade into annular cutting position and then rotating the housing so as to form the circumferential cut.

BRIEF DESCRIPTION OF THE FIGS.

[0016]FIG. 1 is an assembly view of one embodiment of the invention.

[0017]FIG. 2 is an exploded view of FIG. 1.

[0018]FIG. 3 is another embodiment of the plunger.

[0019]FIG. 4 is a sectional view of FIG. 3

[0020]FIG. 5 is an exploded view of the rollers of FIG. 3.

[0021]FIG. 6 shows another embodiment of the invention with cutter in cutting position.

[0022]FIG. 7 shows the embodiment of FIG. 6 with cutter in retracted position.

DESCRIPTION OF A BEST MODE

[0023] Turning now to a discussion of the drawings, FIG. 1 is an assembly view and FIG. 2 is an exploded view of an embodiment of the invention.

[0024] There is shown a plunger 12 which, in the embodiment of FIG. 1, is simply a bar that telescopes into a housing 14. The plunger (bar) 12 has a slot 16 for carrying a blade 18 that has a cutting edge 21.

[0025] A cable 20, having a sheath 19, is positioned in hole 22 through the housing 14. The cable 20 is clamped between plunger 12 and roller 24 rotabaly mounted inside housing 14. The blade 18 preferably has a cutting edge 21 that penetrates the cable 20 by a depth equal to the thickness of the sheath 19. When the user forces the plunger 12 against the cable 20 and pulls the cable 20 through the hole 22, the cutting edge 21 cuts a longitudinal slit in the sheath.

[0026] The cable 20 is then withdrawn from the hole 22 The sheath 19 is peeled back from the cable 20 and cut from the rest of the cable 20.

[0027]FIGS. 3, 4, and 5 show another embodiment in which a pair of concave rollers 26 are mounted on the end of bar 12B. The rollers 26 are not visible in FIG. 3 however FIG. 4 is a sectional view of bar 12B showing rollers 26. FIG. 5 shows the rollers 26 This embodiment has the advantage that the entire circumference of the cable around the blade has rolling support which greatly reduces the amount of force required to pull the cable 20 through the stripper 10.

[0028]FIG. 1 also shows a second cutter blade 28 slidably mounted on the side of housing 14. When performing the axially directed cut, second cutter blade 28 is located in retracted position B disengaged from the cable 20. After the axially directed cut is made, the first cutter 18 is retracted by sliding the plunger 12 away from the roller 24 to unclamp the cable 20. Then blade 28 is slid into cutting position A. The device 10 is then rotated on the cable to form a circumferenmtial cut that completely cuts off the sheath 19.

[0029] Variations and modifications of this invention may be contemplated after reading the specification and studying the drawings which are within the scope of the invention. For example, the housing and plunger Shawn in FIGS. 1-3, the plunger has a square cross section. However, it will be understood that, in another embodiment, the plunger and housing has a round cross section.

[0030] The plunger 12 (bar) is shown to be solid in the drawings however in yet another embodiment, the plunger is a tube that telescopes into the housing 14.

[0031]FIGS. 6 and 7 are two sectional views which show another version of the invention. In FIG. 7, the cutter 12 is retracted to permit positioning the cable between roller 24 and sruface 17 of plunger 12. In FIG. 6, the plunger 12 is moved into position to cut sheath 19. A spring 27 urges the plunger 12 toward the roller 24 so that. cutter 18 penetrates sheath 19. A pin 31 through bar 12 extends through slots 29A and B in housing 14. When it is required to insert the cable 20 into cutting position between roller 24 and plunger 12, the user squeezes handle 23 on pin 31 toward fixed handle 25. The squeeze of handle 23 toward fixed handle 25 is illustrated by arrow X (FIG. 6). Roller 24 is thereby separated from bar 12 (FIG. 7) thereby enabling the user to insert the cable 20 into cutting position through opening 33 in the side of housing 14 as illustrated by arrow Y in FIG. 7. When handle 23 is released, spring 27 forces bar 12 toward roller 24.

[0032] In the version of FIG. 1, the housing 14 has an open end permitting user to press directly on plunger 12 to force cutter 21 into the sheath. In the version of FIGS. 6 and 7, access to forcing the plunger is provided by handle 23 and the housing 14 has a cap 15 that serves as a stop for spring 21.

[0033] In view of such variations that are within the scope of the invention, I therefore wish to define the scope of my invention by the appended claims. 

I claim:
 1. A tool for stripping an insulating sheath from a cable which comprises: a plunger; one cutting blade mounted on said plunger with a cutting edge extending from one surface of said plunger; a housing configured to permit positioning said plunger inside said housing in a cutting location and a retracted location; means for positioning said plunger in a selected one of said cutting and retracted locations; a single roller rotatably mounted inside said housing; said housing having a cable opening means for permitting said cable to be located through said housing; said housing, single roller, plunger, one cutting blade, and cable opening means arranged in operable combination to enable a user to insert said cable through said cable opening means with one side of said cable facing said roller and an opposite side of said cable facing said one surface of said plunger, then force said plunger from said retracted location to said cutting location where said one cutter edge is positioned through said sheath, then pulling said cable through said cable opening means whereby an axially directed slit is formed in said sheath enabling said user to peel and cut said sheath from said cable.
 2. The tool of claim 1 wherein said means for positioning comprises:: said housing having a plunger opening; said plunger dimensioned to telescope through said plunger opening into said housing providing a user access to force said plunger from said retracted location to said cutting location.
 3. The tool of claim 1 wherein said cable opening means comprises a pair of cable openings, each one of said cable openings on a side of said housing opposite a cable opening on an opposite side of said housing.
 4. The tool of claim 1 wherein said cable opening means comprises a single cable opening arranged to enable a user to position said cable between said roller and said one surface of said plunger at any selected location on said cable.
 5. The tool of claim 1 wherein said single roller rotates on its axis perpendicular to a sliding direction of said plunger and perpendicular to an axis of said cable positioned in said housing through said cable openings.
 6. The tool of claim 1 wherein said plunger comprises; a slot extending from said one surface of said plunger; said one cutting blade secured in said slot having one cutter edge engagable with said sheath of said cable positioned through said aperture in said housing when said plunger is forced against said cable.
 7. The tool of claim 2 wherein said housing and said bar have a cylindrical cross section.
 8. The tool of claim 2 wherein said housing and said bar have a rectangular cross section.
 9. The tool of claim 1 further comprising: a pair of rollers mounted on said one surface of said plunger, each one of said pair of rollers rotatably mounted on a side of said cutter blade opposite said other roller on another inside of said cutter blade; said pair of rollers and said single roller rotatably positioned inside said housing all arranged in operable combination to permit that said cable pulled through said pair of cable openings is rotatably supported on said pair of rollers on one side of said cable and said single roller on an opposite side of said cable;
 10. The tool of claim 9 wherein each one of said pair of rollers has a concave surface substantially conforming to a curvature of a surface of said cable.
 11. The tool of claim 1 wherein said single roller has a concave surface substantially conforming to a curvature of a surface of said cable.
 12. The tool of claim 1 further comprising: an axially directed slot in a side of said housing; a pin having one end secured in a side of said plunger and extending through said axially directed slot in said side of said housing whereib said plunger located at said cutting location corresponds to said pin abutting one end of said slot and said plunger located at said retracted location corresponds to said pin abutting another end of said slot.
 13. The tool of claim 12 further comprising: a compression spring located between another surface of said plunger opposite said one surface of said plunger and an internal surface of said housing operably arranged to force said one surface of said plunger toward said roller.
 14. The tool of claim 1 further comprising another cutter blade slideably secured on a side of said housing and arranged to slide another cutting edge of said another cutter blade against said cable extending out through one of said cable openings providing that, when said one cutting edge is disengaged from said cable, a user is enabled to pull said cable positioned in said cable openings through said housing thereby forming an axially directed slit in said sheath, and said user is then enabled to slide said another cutter blade into contact with said sheath and circularly cut said sheath by rotating said housing around an axis perpendicular to said cable.
 15. A tool for stripping an insulating sheath from a cable which comprises: a housing; a plunger configured to permit positioning said plunger inside said housing in a selected one of a cutting location and a retracted location; one cutting blade having a cutting edge; said cutting blade mounted on said plunger and extending from one surface of said plunger; a single roller rotatably mounted inside said housing; an axially directed slot in a side of said housing; a pin having one end secured in a side of said plunger and extending through said axially directed slot in said side of said housing whereby said plunger located at said cutting location cooresponds to said pin abutting one end of said slot and said plunger located at said retracted location corresponds to said pin abutting another end of said slot; a compression spring located between a surface of said plunger opposite said one surface of said plunger and an internal surface of said housing operably arranged to force said one surface of said plunger toward said roller; said housing having a cable opening means for enabling said cable to be located through said housing between said roller and said one surface of said plunger; said housing, single roller, plunger, one cutting blade, and cable opening means arranged in operable combination to enable a user to insert said cable through said cable opening means with one side of said cable facing said roller and another side of said cable facing said one surface of said plunger, then force said plunger from said retracted location to said cutting location where said one cutter edge is positioned through said sheath, then pulling said cable through said cable opening whereby an axially directed slit is formed in said sheath enabling said user to peel and cut said sheath from said cable. 